Fluid pressure tool



May 1927 E. PENBERTvl-w 1629117 FLUID PRESSURE TOOL Filed Jan. 27, 3.925

Patented May 177, 1927.

,ERNEST fPE'NBERTfHY, 0F manoir, afnemen, `'esSfl'veefr@ Cinese@ RNE/uumlr! 'rootI COMPANY, oF New ,YLOLRKHN Y., A coaronn'rron I:or lNEW Itifnnss'av.

FiiUrDrRnssURE Toor...`

Application filed January -This invention relates to fluid pressurepercussive tools of the type usinga two-diameter piston. While such tools are. oi general 'utility they are Vparticularly adapted for use instoping or drilling upwardly inclined holes duringmining operations. The `present invention is in some respects animprove-V ment on a previous invention disclosed in my co-pending applicationl Serial No. 5002 iled of even date'herewith.`

Among the objects of the invention are to increase the piston speed Of a drill ofthis type by providing` a quick acting positive cushion for stopping the lpiston at the end of its stroke without striking the cylinder or head of the tool, tofprovide v`an improved form of two diameter piston for accomplishing the aboveobject, and in generalto improve prior devices in the'interest of more efficient and satisfactory operation.

lith these and other objects in. mind the linvention will now be described in .detail reference being had to the-accompanying v' so drawings wherein is disclosed forthe pur 1pose of illustration certain preferred vembodiments thereof. n

In the drawings: y l

l'Figi 1 isalongitudinal sectional view of so much of. a stoping drill as is necessary to illustrate vthe invention. l Y

fFig. 2 is a 'fragmentary sectional view similar toFig. 1 showing theoperative parts oi the drill in a vdifferent position.

Fig. 8 is a fragmentary,sectional view similar to Fig. 1 ofamodiiled formofthe invention the operative parts being` vshown rin the positionillustrated .inilllg 2.

In the embodiment of theinvention disclosed in- Figs'.v 1 and 2 the drill cylinder l provided at. its rear or bac-lr end with 1a feed'cylinder 5fofany knownor desired type and at its opposite end with a front :head 6 'forming a chuck for the shank of the drill bit or steel "Z whichreceives through an anvil 8 mounted in a `guide member z9' interposed betweenhead and cylinder 4l the blows 'of the impact member ornpistonglOof Fthe drill.I l Y l As in mycopending application above referred yto cylinder 4 provides a two diameter y controlled exhaust forthe,I rearifaceof the f pistonfchamber in -whichis disposed thetwo `vber and a rearwardly .projecting stem 10b iittingthe small borey @of thevpiston chamber. The stem end of the pistonl() is continuously subjected to the pressure ofmotive fluidadmit-tedto the live air chamber11 of the cylinder by the usual throttle valve 12. The second forward pressure area vofthe piston, namely the rearfface of head lOafhas motive fluid admitted thereagainstk and eX-i ihausted therefrom ,by an automaticv control valve 13 reciprocating ina valve chamber 13a in timed relation with the movements of the pistonj-lO `and serving alternately .to,e.f fectconn'ectionof passage 14: with theflive airA passage 11a4 (Fig. 1) orwith the auxiliary exhaust port 15 (fFigzQ). :This valve, as in. my copending application, is shifted rearwardly through the` building up of pressure against the forward end thereof resultfrom which groove extendsa passage-203130 'the rear endof thegvalve. .A branchQOLfof vpassage 20 extendsto thel front end ofthe f large` bore ila'fof the piston chamber lto A.adwn'iit motivef'fluid against the-front face .of-piston head,10a;,which serves as the return areal'for y the piston.A lAs in my copen-ding applicationY 'the rearheadgof the valve` onitsfforwand movement may uncover a branch passage lllffronithe live air passage 111H for lcontinuingzthe delivery of motivef-fliliid tothe frontl of the ,pistoii'chamber after the stem 'of the piston hasclosed theadmission groove v19 (Fig. 2). The piston headV l0controls the usualmain exhaust port or groove 21 which communicates with exhausty passage 21a^leadingtoatmosphere. K 1 Y Y Sincethe cycle of operationofthe Idrillas `,so far CleSCll'JeCl :is bclievedto be olwious'andv v moreover is identical with thatoflv aldrifll dis closed .in my above pidentied copending. .ap-V

Aplication v further A"description"- thereofvis omitted. 1 Y y K v v By the combination of theauXi-liary ivalve piston head 10? togetherwith the valve con'-V VtrolledA means-for delayingthepcutoftz ofthe v A 1motive-ftluid supply.v to the front or;` zreturn pressure i area' l of; the piston,l` afterglts.` stem Vhas closed the usual admission groove 19,

a fullrearward stroke of the piston even aga-instv the constant live air pressure on the valvestemrls insured. It 1s -essential to the fast operation ofthe drill and to the prevention of damage to' the latter by a possible Yst-rikingof the piston that effective scribed.

means be provided for .positively and `promply checking and reversing the piston at the endof its rearward stroke. lMeans for accomplishingthis purpose, which comprises'the present invention, will now be de- The stem l0b of the piston ladjacent itsconnect-ion with the head l0a is Vformed with an enlargement 22 providing Va shoulder 222L adj acent stem lO"l and this enlargement has a fluid tight sliding lit in` counter bore 23 of the small bore 4t of the cylinder. Vith this arrangement the sealing or closing of the counter bore 23 by the enlargement 22 on the rear stroke of theA ing fit with the counter bore 23, this dispositionk of the vent passage not only insures a tight seal of the same but makes for accurately timed shifting of the valve as the trapped and compressed air in the cushion chamber augments the continuously advmitt'ed'stream of motive fluid from passage '1G-17. air insures an ample air cushion in counter- V -bore 23.

The invention further contemplates a re- Versiblepiston having the characteristics of the nonreversible piston just described. To

this end a'modilication of the invention is w shown in Fig. 3 wherein slight changes in .the front head construction of the drill are required to accommodate the reversible piston'. These changes are such as to provide 1f desired an lair cushion for the piston on its forward stroke 4as vwell as its rearward stroke whereby the strikingV of the piston and lpossible damage to the front head constructionofv the drill is avoided in case the drill isinadvertently operated when the drill steel is not in" placeoris not pressed Vto thework. As shown the reversibley piston 30 (Fig. 3) comprises a cylinder head porl tion il tting the large bore la of the drill cylinder l withfsymmetrical disposed exten-r sions on opposite sides offthis head. These extensions comprise the yenlargements 30'p Conversely continuously admittedv adjacent the head (corresponding to the enlargement .22 on piston l0) and projecting stem portions 30h. j The rearwardly disposed stem portion 30b reciprocates within the small bore All" of the piston chamber and the rearwardly disposed enlargement 30c coop- Ver'ates with the counterbore 23 in the piston chamber after the manner described in relation to the form ofthe invention shown in Figs. land 2. The front stem portion 30 of the piston imparts the blows of the piston directly to the drill steel 7 supported in th'effront head 6 and reciprocates in the bore of a guide member 9- which is inte'r-l e posed between the front head 6 and cylinder l of the drill. Guide member 9 is counterbored at 9*to receive forward enlargementy 30u with a sliding fit, whereby an air` cushion is formed' for thefrontshoulder 3l of the piston. guide member 9 is so disposed V'as not to interfere with the full blow of the piston and to produce the cushion chamber only when the piston moves forward to an undue extent as when there is no steel in the front head or when the steel is not pressed to the work. With the exception that the revers- The counterbore Y9" ofthe 5 ible piston strikes the drill steel directly and is cushioned and stoped only when it moves forward to an undue extent, the functioning of the Vreversible piston in the slightly modified form of drill shown in F ig. 3 is exactly the same as the functioning of the non-reversible piston shown in Figs'. l and 2.

I claim as my invention: y

l. In a fluid pressure tool, in combination,` a cylinder having coaxial interconnected large and small bores, a piston formedA with a head tting the large bore and a stem fitting the small bore and arrangedV to be reciprocated in said cylinder, thefsrnall bore of said cylinder being counterbored to form a cushion chamber, and an enlargement on the stem of said piston for cooperation withA Ysaid counterbore near the end of the piston stroke for cushioning the piston. Y

2. In a fluidpressure tool,in combination, a cylinderk having coaxialinterconnected large and small bores, a'piston formed with a head fitting the .large bore Vand a stem` fitting the small bore and arranged to be reciprocated in said cylinder, thesmall `bore ofsaid cylinder being counterbored to form a.A cushion chamber, an enlargement on the stem of said piston for cooperation with said counterbore near the end of the piston stroke for cushioningthe piston, andmeans admitting motivey fluid to` said counterbore.

3. In aV fluid pressure tool, in combination,

.a cylinder having coaxial interconnected large and small bores, a piston formed with a head fitting'y the large bore anda stemVv fitting thev smallbore andxarran'gedto be reciprocated in said cylinder, the small bore loo fini' of said cylinder being counterbored to form a cushion chamber, an enlargement on the j stem of said piston for cooperation with said counterbore near the end of' the piston stroke for cushioning the piston, and a port con trolled by said enlargement admitting motive fluid to said countcrbore.

4. In a fluid pressure tool, in combination, a cylinder havingV a two diameter bore, a piston reciprocable in said bore and formed with a head and a projecting stem to lit said bore, a valve controlling the movements of said piston, an enlargement on said piston stem arranged to control the shifting of the valve in one direction, said cylinder having a counterbore for receiving said enlargement thereby forming a cushion chamber to check the movement of said piston.

5. In a fluid pressure tool, in combination, a cylinder having atwo diameter bore, a piston reciprocablein said bore and yformed with a head and a projecting stem tol fitvsaid bore, a symmetrical enlargement on the stem 'of said piston cooperating with a counterbore in the small bore of said cylinder to cushion the piston at the end of' its stroke, a valve controlling the movements of said piston, and a passage admitting live air continuously to a pressure area of said valve, said passage terminating in a ventor relief port in said counterbore whereby on sealing of said counterbore by said enlargement 'an effective air cushion is provided by said continuously admitted live air, which live vair Vis also caused to build up against said pressure area and shift said valve.

6. In a fluid pressure tool, in combination, a cylinder having coaxial interconnected large and small bores, the small bore having a counterbore adjacent the large bore, a piston reciprocable therein having 'a head fitting the large bore and a stem of' uniform diameter fitting the small bore, 'means for venting the piston chamber rearwardly of said head on the back stroke of said piston, and means for cushioning said piston comprising an enlargement on said stem cooperating with said counterbore in'said small cylinder bore. j

7. In a fluid pressure tool, in combination, a cylinder'having a two diameter bore, the small bore having a counterbore adjacent the large bore, a reversible piston reciprocable therein comprising a head with projections or stems extending from the pposite sides thereof, said stems having enlargements adjacent said head for cooperation with said counterbore in said cylinder for cushioning said piston at the end of its Stroke. A Y

8. In a fluid pressure tool, Iin combination, a cylinder having a two diameter bore', a reversible piston reciprecable thereinrcomprising a head with projections or stems extending from the opposite sides thereof, said stem having enlargements adjacent said head, said cylinder having a counterbore at one end of the small piston bore thereoffor cooperation with the rearwardly disposed enlargement to form a cushion chamber,'and a guide for the front or impact stem of the piston, said guide having a counterborefor receiving the forwardly disposed enlargement thereby to form a cushionchamber.,

9. A ypiston for fluid pressure percussive tools comprising a cylindrical head having a projection or stem extending from one face. of said head, said stem being of uniform diameter throughout its length save for an enlargement extending radially therebeyond v to form a. cushion surface' disposed transversely to the longitudinal axis of said piston.

10. A piston for fluid pressure percussive tools comprising a cylindrical head having projections or stems extending axially from the opposite faces of said head, an enlargement -on one of' said stems adjacent said head said enlargement providing a cushion surface disposed transversely to the longitudinal axis of said piston, said stems being of Vuniform diameter beyond said enlarge? ments.

11. A reversible piston for fluid pressure percussive tools comprising a cylindrical head having projections or stems extending axiallyfrom the opposite faces of said head, and enlargements on both of said stems adjacent said head,` said enlargements .providing cushion vsurfaces disposed transversely y to the longitudinal axis ofsaid piston, said V stems being of uniform diameter beyondv said enlargements. g

Signed by me at Detroit, Mich., this 21st day of January, 1925.'

ERNE ST PENBERTHY. 

